The perfect fit

When choosing a new bicycle, it is very important to buy the correct size for you. If the bike is of the wrong size, not only will it be uncomfortable to ride, but it may also be dangerous. In particular, when buying bikes for children, it's always tempting to buy slightly too big in order to give them room to grow. However, this can be particularly dangerous, especially if they're not yet very confident cyclists.

The problem with bicycle sizes is that every manufacturer has a slightly different idea as to what shape a frame should be, so they all end up measuring them slightly differently. Whilst you can may have some idea of what size you want, it is impossible to be confident without trying them out in person.

The standard rule of thumb is to check the standover height. This is the distance between your lowest point between your legs (crotch) and the tube that runs along the top of the frame when you stand astride the bike, in front of the saddle, with both feet flat on the floor. For off-road cycling, this should be about three to four inches, in case you have to stop in a hurry and the ground is uneven. For on-road cycling, you can get away with a little less, maybe two inches.

Everything else can be adjusted by moving the position of the saddle, and adjusting the stem. Of course, it is possible to ride bikes with more standover height than you need by making these adjustments, but this often leaves you leaning over the front wheel a bit too much, which makes handling difficult.

The test ride

When you take your potential bike purchase out for a ride, you should make sure it's reasonably set up first. It may take a little while to find the exact configuration that is most comfortable, you should definitely make sure that you can touch the floor without hurting yourself, otherwise the first junction you come to could be painful...